Method of and apparatus for roentgenographic inspection



Patented Mar. 9, 1948 METHOD OF AND APPARATUS FOR ROENT- GENOGRAPHIC IN SPECTIQN No Drawing. Application February 25, 1942, Serial No. 432,286

5 Claims.

My invention relates to improvements in the inspection of articles for hidden flaws by the use of X-rays and has for its object the elimination of the confusion sometimes occurring when a radiographic negative and the article from which the negative was made become separated in the processing after exposure, and a consequent uncertainty is introduced as to the identity of the article from which a given radiograph Was made.

In the practice of my invention, the article to be radiographed is sensitized by coating an exterior surface with a. photosensitive deposit, preferably of the nature of a photographic emulsion. The article, With the photosensitive deposit thereon, is exposed to the radiation from the X-ray tube, with the side of the article which has been sensitized so located that the radiation passes through the body being inspected before impinging on the photosensitive deposit. Obviously, the article being inspected may be completely covered with the photosensitive deposit, in which case it will be unnecessary to orient the mass of the body with respect to the direction of incident radiation.

After exposure, the image is fixed by means well known in the art and constitutes a record, inseparable from the article which originated it, and directly useful in conducting repairs, if such be found .desirable. For example, a blow-hole or porous spot in a flange may be chipped out directly from the radiographic record, and a weld repair conducted.

If the article has been covered on both or all exterior surfaces, as by immersion in a photosensitive solution, the exposure on the proximate face, which should be completely overexposed to a uniform density, may be used as a check on the articles having been in the radiation field of the tube.

In the following claims, the phrase irreversibly-photosensitive is intended to describe that class of materials Which are sensitive to shortwavelength electromagnetic radiations; and in which materials the characteristics acquired by exposure to such radiation are not appreciably diminished upon removal of the material from the radiation field.

The article may require to be pretreated to receive the photosensitive deposit and secure the uniform adhesion thereto. A wide range of such treatments is well known in the art: for example, after cleaning the article, a protective cellulose lacquer coating of contrasting color may be applied to the surface, followed by a, photosensitive coating adherent to the lacquer coating. The.

neutral lacquer coating here protects the photosensitive deposit from the chemical action of the impurities in the article, and also protects the article from the chemical action of the fixing solutions after exposure. If the article has a large flat surface, the photosensitive deposit may be made by gluing or otherwise fastening a sheet of photosensitive paper to said flat surface, developing and printing said paper while retaining same in contact with the article being radiographed.

I claim:

1. In the radiographic inspection of an article, an irreversibly-photosensitive deposit adherent to a surface of said article within an umbra formed by the interception of the incident radiation by the said article, said adherence being continuous during the exposure and development of the image produced on said deposit as a result of the transmission of said radiation through said article.

2. In the radiographic inspection of an article, a neutral deposit adherent to said article and an irreversibly-photosensitive deposit adherent to said neutral deposit on a surface of said article within an umbra formed by the interception of the incident radiation by the said article, said adherence being continuous during exposure to said radiation and development of the image produced on said deposit as a result of the transmission of said radiation through said article.

3. In the radiographic inspection of an article, the steps of afiixing an irreversibly-photosensitive sheet to a surface of said article within an umbra formed by the interception of the incident radiation by said article, and retaining said sheet in affixed contact with said article continuously during exposure to said radiation and development of the image produced on said sheet as a result of the transmission of said radiation through said article.

4. In the radiographic inspection of an article, the production of an image on an irreversiblyphotosensitive surface having a fixed spatial relation to the said article, said surface being located Within a penumbra formed by the interception of the incident radiation by said article, and said fixed spatial relation being maintained continuously during exposure to said radiation and development of the image produced on said surface as a result of the transmission of said radiationthrough said article.

5. In the radiographic inspection of an article, the production of an image on an irreversiblyphotosensitive surface amxed to and superimposed on said article within a penumbra formed by the interception of the incident radiation by 3 said article, said aflixation and superimposition being prior to exposure to said radiation and being maintained continuously during the development of the image produced on said surface as a result of the transmission of said radiation 5 through said article.

JOHN J. MOYNIHAN.

REFERENCES CITED The following references are of record in the 10 file of this patent:

UNITED STATES PATENTS Number Name Date 441,086 Dobinson Nov. 18, 1890 15 Number 

